I’m not experiencing any problem either.
From experience I do know that you may end up with double scrobbles when stopping playback mid-track and them restarting it a bit later. Although I’m not sure, I believe a scrobble is registered after 1 min of playback.
Other potential sources I can think of:
- Multiple zones playing independently of each other
- Timezone settings of device running Roon
- Timezone settings in Last.fm